Stayed at Tall Pines resort on Wabaskang a few years ago, and had a pretty good time. We did decent for walleye (20-50 a day), but there are also a bunch of options for pike and perch, if the kids want to do something different. Cabins and resort were in great shape, and the drive was pretty easy.
Another one I’ve done is Dogtooth, which is just east of LOW and a short drive across the border. They have things like kayak rentals and a swim platform and slide for the kids, but also the potential for 15lb walleye! I wouldn’t expect numbers there though, so that might put a damper on it for he kids. We did find a back bay that let us put the hammer on a few dozen 10-14″ crappie though, I’m sure that would be a blast for them. It’s also a relatively short drive to Kenora, which has pretty much anything you need, and would be a good option if some of the group wanted to spend a day away from the resort.
There are a ton of options in Ontario, so narrowing down your search by prioritizing what you care most about might help. Creature comforts and amenities? Quality of fishing? Remoteness, or lack thereof? Price can also be a deciding factor, as well as things like American plans or boat rentals and guides, depending on what you’re looking for.